Hydrothermal Synthesis, Crystal Structure and Magnetic Properties of Lithium Manganese Complex of Benzene-Hexacarboxylic Acid (Mellitic Acid)

A new mellitate complex LiMn[C(6)(COO)(6)](0.5)(H(2)O)(2) (1) has been synthesized by the reaction of mellitic acid and Mn(OAc)(2)center dot 4H(2)O in the presence of LiOH center dot H(2)O. 1 was characterized by the elemental analyses, IR spectra, TGA and the single crystal X-ray diffraction. X-ray crystal structural analysis revealed that the Li cation has a distorted tetrahedral geometry, coordinated by three carboxylic oxygen atoms and one water molecule. The Mn cation is coordinated to one water molecule and five carboxylic oxygen atoms in a slightly distorted octahedral coordination geometry. The mellitate anions behave as a bridging ligand and link six lithium ions and eight manganese ions repeatedly to form an interesting three-dimensional metal-organic coordination polymer. Variable-temperature magnetic susceptibility measurements indicate the presence of antiferromagnetic behavior.